Electronic device and method in wireless communication system, and wireless communication system

ABSTRACT

An electronic device at a base station end includes a processing circuit, the processing circuit being configured to: configure, in response to request signalling from a user equipment, an aperiodic beam-forming reference signal relevant to a first beam group for the user equipment, wherein the first beam group is determined by a base station according to channel state information periodically fed back by the user equipment; generate downlink control information, so as to indicate that the user equipment feeds back beam selection information according to the aperiodic beam-forming reference signal; determine, according to the beam selection information, one or a plurality of candidate beams and one or a plurality of corresponding second pre-coding codebooks; and determine an effective pre-coding codebook based on the one or multiple second pre-coding codebooks.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.17/023,392, filed Sep. 17, 2020, which is a continuation of U.S.application Ser. No. 16/809,560, filed Mar. 5, 2020 (now U.S. Pat. No.10,804,986), which is a divisional of U.S. application Ser. No.16/314,661, filed Jan. 1, 2019 (now U.S. Pat. No. 10,630,354), which isbased on PCT filing PCT/CN2017/093807, filed Jul. 21, 2017, which claimspriority to CN 201610694565.3, filed Aug. 19, 2016, each of which isincorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present disclosure relates to the field of wireless communicationtechnology, and particularly to an electronic device and method forselectively adjusting a Precoding Matrix Indicator (PMI) fed back by auser equipment in a wireless communication system, and a wirelesscommunication system.

BACKGROUND OF THE INVENTION

As the main target of R14, 3D Multi-Input Multi-Output (3D MIMO)enhancement mainly comprises improving the robustness of an actualdeployment scenario, which at least shall include a high speeddeployment scenario.

In a high speed scenario, it is generally recommended to use a largermeasurement and report period, because a PMI with a short report periodwill cause a performance loss due to quick changes in channels. However,in this case, in view of measurement and feedback latency, Channel StateInformation (CSI) fed back by a user possibly fails to precisely reflectchannel states. The CSI generally comprises information such as PMI,Channel Quality Indicator (CQI), Rank Indicator (RI) and the like. Thatis, the PMI fed back is possibly expired, which will cause a mismatchedprecoding strategy. Thus, it is desired to make it possible to provide asolution capable of adjusting the PMI fed back, so as to solve theproblem of expiration of the PMI in the high speed scenario.

SUMMARY OF THE INVENTION

A brief summary of the present disclosure is given below to provide abasic understanding of some aspects of the present disclosure. However,it should be understood that the summary is not an exhaustive summary ofthe present disclosure. It does not intend to define a key or importantpart of the present disclosure, nor does it intend to limit the scope ofthe present disclosure. The object of the summary is only to brieflypresent some concepts of the present disclosure, which serves as apreamble of the more detailed description that follows.

In view of the foregoing problem, an object of at least one aspect ofthe present disclosure is to provide an electronic device and method ina wireless communication system, and a wireless communication system,which are capable of triggering, according to a communication quality ofa user equipment, selective adjustment on a PMI fed back by the userequipment.

According to an aspect of the present disclosure, there is provided anelectronic device at base station end in a wireless communicationsystem, the electronic device comprising a processing circuitryconfigured to: configure, in response to a request signaling from a userequipment, a non-periodic beamformed reference signal related to a firstbeam group for the user equipment, the first beam group being determinedby the base station according to channel state information periodicallyfed back by the user equipment; generate downlink control information toinstruct the user equipment to feed back beam selection informationaccording to the non-periodic beamformed reference signal; determine,according to the beam selection information, one or more candidate beamsand one or more second precoding codebooks corresponding to the one ormore candidate beams; and determine an effective precoding codebookbased on the one or more second precoding codebooks.

According to another aspect of the present disclosure, there is furtherprovided an electronic device at user equipment end in a wirelesscommunication system, the electronic device comprising a processingcircuitry configured to: determine whether a communication qualitybetween the user equipment and a base station is lower than apredetermined threshold; generate, in a case where it is determined thatthe communication quality is lower than the predetermined threshold, arequest signaling to be sent to the base station, to request the basestation to configure a non-periodic beamformed reference signal relatedto a first beam group for the user equipment, the first beam group beingdetermined by the base station according to channel state informationperiodically fed back by the user equipment; and generate, in responseto downlink control information from the base station, beam selectioninformation to be sent to the base station according to the non-periodicbeamformed reference signal, for the base station to determine aneffective precoding codebook based on the beam selection information.

According to another aspect of the present disclosure, there is furtherprovided a wireless communication system comprising: a user equipmentcomprising a first processing circuitry configured to: determine whethera communication quality between the user equipment and a base station islower than a predetermined threshold, generate, in a case where it isdetermined that the communication quality is lower than thepredetermined threshold, a request signaling to be sent to the basestation, and generate, in response to downlink control information fromthe base station, beam selection information to be sent to the basestation according to a non-periodic beamformed reference signal; and thebase station comprising a second processing circuitry configured to:configure, in response to the request signaling, a non-periodicbeamformed reference signal related to a first beam group for the userequipment, the first beam group being determined by the base stationaccording to channel state information periodically fed back by the userequipment, generate the downlink control information to instruct theuser equipment to feed back the beam selection information, determine,according to the beam selection information, one or more candidate beamsand one or more second precoding codebooks corresponding to the one ormore candidate beams, and determine an effective precoding codebookbased on the one or more second precoding codebooks.

According to another aspect of the present disclosure, there is furtherprovided a method at base station end in a wireless communicationsystem, the method comprising: configuring, in response to a requestsignaling from a user equipment, a non-periodic beamformed referencesignal related to a first beam group for the user equipment, the firstbeam group being determined by the base station according to channelstate information periodically fed back by the user equipment;generating downlink control information to instruct the user equipmentto feed back beam selection information according to the non-periodicbeamformed reference signal; determining, according to the beamselection information, one or more candidate beams and one or moresecond precoding codebooks corresponding to the one or more candidatebeams; and determining an effective precoding codebook based on the oneor more second precoding codebooks.

According to another aspect of the present disclosure, there is furtherprovided a method at user equipment end in a wireless communicationsystem, the method comprising: determining whether a communicationquality between the user equipment and a base station is lower than apredetermined threshold; generating, in a case where it is determinedthat the communication quality is lower than the predeterminedthreshold, a request signaling to be sent to the base station, torequest the base station to configure a non-periodic beamformedreference signal related to a first beam group for the user equipment,the first beam group being determined by the base station according tochannel state information periodically fed back by the user equipment;and generating, in response to downlink control information from thebase station, beam selection information to be sent to the base stationaccording to the non-periodic beamformed reference signal, for the basestation to determine an effective precoding codebook based on the beamselection information.

According to another aspect of the present disclosure, there is furtherprovided an electronic device at base station end in a wirelesscommunication system, the electronic device comprising a processingcircuitry configured to: configure, in response to a request signalingfrom a user equipment, a non-periodic beamformed reference signalrelated to a first beam group for the user equipment, the first beamgroup being determined by the base station according to channel stateinformation periodically fed back by the user equipment; and generatedownlink control information to instruct the user equipment to feed backa non-periodic Precoding Matrix Indicator according to the non-periodicbeamformed reference signal.

According to another aspect of the present disclosure, there is furtherprovided an electronic device at user equipment end in a wirelesscommunication system, the electronic device comprising a processingcircuitry configured to: determine whether a communication qualitybetween the user equipment and a base station is lower than apredetermined threshold; and generate, in a case where it is determinedthat the communication quality is lower than the predeterminedthreshold, a request signaling to be sent to the base station, torequest the base station to configure a non-periodic beamformedreference signal related to a first beam group for the user equipment,the first beam group being determined by the base station according tochannel state information periodically fed back by the user equipment.

According to other aspects of the present disclosure, there is furtherprovided a computer program code and a computer program product forimplementing the foregoing methods according to the present disclosure,and a computer readable storage medium having stored thereon thecomputer program code for implementing the foregoing methods accordingto the disclosure.

According to embodiments of the present disclosure, by selectivelytriggering, according to a communication quality of a user equipment, abase station to send a non-periodic beamformed reference signal so as toselectively adjust a PMI fed back by the user equipment, it is madepossible to avoid the problem of mismatching a precoding strategy causedby an expired PMI, thereby optimizing the system performance.

Other aspects of embodiments of the present disclosure will be given inthe following specification part, wherein preferred embodiments forsufficiently disclosing embodiments of the present disclosure aredescribed in detail, without applying limitations thereto.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure can be better understood with reference to thedetailed description given in conjunction with the appended drawingsbelow, wherein throughout the drawings, same or similar reference signsare used to represent same or similar components. The appended drawings,together with the detailed descriptions below, are incorporated in thespecification and form a part of the specification, to further describepreferred embodiments of the present disclosure and explain theprinciples and advantages of the present disclosure by way of examples.In the appended drawings:

FIG. 1 is a schematic view showing a high speed deployment scenario;

FIG. 2 is an overall flowchart showing an exemplary process of a PMIadjustment solution according to an embodiment of the presentdisclosure;

FIG. 3 is a schematic view showing an exemplary format of beam selectioninformation according to an embodiment of the present disclosure;

FIG. 4 is a timing sequence diagram showing a PMI adjustment solutionaccording to an embodiment of the present disclosure;

FIG. 5 is a flowchart showing an example of signaling interaction of aPMI adjustment solution according to an embodiment of the presentdisclosure;

FIG. 6 is a flowchart showing another example of signaling interactionof a PMI adjustment solution according to an embodiment of the presentdisclosure;

FIG. 7 is an overall flowchart showing an exemplary process of a PMIadjustment solution according to another embodiment of the presentdisclosure;

FIG. 8 is a block diagram showing a function configuration example of anelectronic device at base station end in a wireless communication systemaccording to an embodiment of the present disclosure;

FIG. 9 is a block diagram showing a function configuration example of anelectronic device at base station end in a wireless communication systemaccording to another embodiment of the present disclosure;

FIG. 10 is a block diagram showing a function configuration example ofan electronic device at user equipment end in a wireless communicationsystem according to an embodiment of the present disclosure;

FIG. 11 is a block diagram showing a function configuration example ofan electronic device at user equipment end in a wireless communicationsystem according to another embodiment of the present disclosure;

FIG. 12 is a block diagram showing a configuration example of a wirelesscommunication system according to an embodiment of the presentdisclosure;

FIG. 13 is a flowchart showing a process example of a method at basestation end in a wireless communication system according to anembodiment of the present disclosure;

FIG. 14 is a flowchart showing a process example of a method at basestation end in a wireless communication system according to anotherembodiment of the present disclosure;

FIG. 15 is a flowchart showing a process example of a method at userequipment end in a wireless communication system according to anembodiment of the present disclosure;

FIG. 16 is a flowchart showing a process example of a method at userequipment end in a wireless communication system according to anotherembodiment of the present disclosure;

FIG. 17 is a block diagram showing an exemplary structure of a personalcomputer used as an information processing apparatus usable in anembodiment of the present disclosure;

FIG. 18 is a block diagram showing a first example of a schematicconfiguration of an evolutional node (eNB) to which the technologyaccording to the disclosure can be applied;

FIG. 19 is a block diagram showing a second example of a schematicconfiguration of an eNB to which the technology according to the presentdisclosure can be applied;

FIG. 20 is a block diagram showing an example of a schematicconfiguration of an intelligent telephone to which the technologyaccording to the present disclosure can be applied; and

FIG. 21 is a block diagram showing an example of schematic configurationof an automobile navigation device to which the technology according tothe present disclosure can be applied.

EMBODIMENTS OF THE INVENTION

Hereinafter, exemplary embodiments of the present disclosure will bedescribed in detail in conjunction with the appended drawings. For thesake of clarity and conciseness, the specification does not describe allfeatures of actual embodiments. However, it should be understood that indeveloping any such actual embodiment, many decisions specific to theembodiments must be made, so as to achieve specific objects of adeveloper; for example, those limitation conditions related to thesystem and services are met, and these limitation conditions possiblywould vary as embodiments are different. In addition, it should beappreciated that although developing tasks are possibly complicated andtime-consuming, such developing tasks are only routine tasks for thoseskilled in the art benefiting from the contents of the presentdisclosure.

It should also be noted herein that, to avoid the present disclosurefrom being obscured due to unnecessary details, only those devicestructures and/or processing steps closely related to the solutionaccording to the present disclosure are shown in the appended drawings,while omitting other details not closely related to the presentdisclosure.

Next, embodiments of the present disclosure will be described in detailwith reference to FIG. 1 through FIG. 21.

FIG. 1 is a schematic view showing a high speed deployment scenario. Asshown in FIG. 1, in the high speed deployment scenario, a user equipment(which for example is an in-vehicle device in the example as shown inFIG. 1) is in movement at speed V. As described above, in a high speedscenario, due to quick changes in channels, it is general to configure alarger measurement and report period. However, such vehicle and feedbacklatency will cause a possibility of expiration of a PMI fed back by theuser equipment; that is, a PMI fed back by the user equipment at acurrent time possibly reflects a channel state at a previous timewhereas at this time the user equipment has moved to a next position,and thus the PMI fed back fails to precisely reflect a channel state ofthe current time. Accordingly, a mismatched precoding strategy will becaused.

One of the objects of the present invention is to propose a solution forsuch a problem. A technical solution according to an embodiment of thepresent disclosure will be described as an example in detail below.

First, an overall concept of a PMI adjustment solution according to anembodiment of the present disclosure will be described with reference toFIG. 2. FIG. 2 is an overall flowchart showing an exemplary process of aPMI adjustment solution according to an embodiment of the presentdisclosure.

As shown in FIG. 2, first, in step S201, a user equipment determineswhether a communication quality between the user equipment and a basestation is lower than a predetermined threshold.

The user equipment will periodically evaluate the communication qualityof itself. The communication quality for example may be evaluated by oneor more of QoS (Quality of Service), CQI (Channel Quality Information),RSRP (Reference Signal Receiving Power) and RSRQ (Reference SignalReceiving Quality) and the like. If the user equipment determines thatthe communication quality at this time is lower than the predeterminedthreshold, it is indicated that the precoding strategy at this time ispossibly improper, that is, it is indicated that the problem ofexpiration of a PMI possibly occurs.

If it is determined in step S201 that the communication quality is lowerthan the threshold, the solution proceeds to step S202. In the stepS202, the user equipment generates a request signaling, to trigger thebase station to configure a non-periodic beamformed reference signalrelated to a first beam group for the user equipment. The first beamgroup is determined by the base station according to channel stateinformation periodically fed back by the user equipment. On the otherhand, if it is determined in the step S201 that the communicationquality is equal to or higher than the predetermined threshold, it isunnecessary to trigger the base station to configure a non-periodicbeamformed reference signal for the user equipment. In the embodiment ofthe present disclosure, the reference signal is for example CSI-RS(Channel State Information-Reference Signal).

Generally, the base station will periodically configure a referencesignal for the user equipment, and the reference signal may benon-precoded or beamformed. In response to the periodic referencesignal, the user equipment will periodically feed back Channel StateInformation (CSI), which generally comprises CQI, PIM and RI, to thebase station, such that the base station can determine a precodingcodebook, denoted as W herein, according to the aforesaid PMI. Theprecoding codebook W generally may be represented as the product of along-term/wideband feedback precoding codebook W₁ and ashort-term/subband feedback precoding codebook W₂, that is, W=W₁×W₂. Itis generally regarded that, the long-term/wideband feedback precodingcodebook W₁ represents long-term/wideband feedback information and thusis not expired, and the short-term/subband feedback precoding codebookW₂ represents short-term/subband feedback information and is possiblyexpired in a high speed condition. The base station may determine thefirst beam group according to the long-term/wideband feedback precodingcodebook W₁ (assuming that it comprises L beams). For the specificprocess concerning how to determine a corresponding precoding codebookaccording to the channel state information periodically fed back by theuser equipment and determine the first beam group, reference may be madeto the related description of the prior art, and description will not berepeatedly made herein.

In a certain embodiment, the request signaling generated by the userequipment may be sent to the base station through for example RRC (RadioResource Control) signaling, via a PUSCH (Physical Uplink SharedChannel). As an exemplary implementation, the request signaling is forexample represented as R1, wherein if R1=1, it is indicated that theuser equipment at this time requires the base station to configure anon-periodic beamformed reference signal related to a first beam groupfor the user equipment.

In step S203, the base station configures a non-periodic beamformedreference signal for the user equipment, according to the receivedrequest signaling, based on the determined first beam group.

In step S204, the base station generates downlink control information toinstruct the user equipment to feed back beam selection informationaccording to the configured non-periodic beamformed reference signal. Asan example, the base station for example may modify the existing DCIformat 0, to utilize a redundant bit or a new added bit therein toinstruct the user equipment to feed back beam selection information. Forexample, one-bit identification information PMI_Adjust_Flag may be set,wherein if PMI_Adjust_Flag=1, it is represented that the base stationrequires the user equipment to feed back beam selection information, andotherwise if PMI_Adjust_Flag=0, it is represented that the base stationdoes not require the user equipment to feed back beam selectioninformation.

As can be seen, by utilizing the redundant bit or the new added bit inthe existing DCI format 0 to instruct the user equipment to feed backbeam selection information, it is made easier to realize thecompatibility with the existing communication protocol. Alternatively,it is also possible to instruct the user equipment to feed back beamselection information by modifying the existing signaling such as DCIformat 1, DCI format 1A and the like.

In step S205, the user equipment generates, in response to the receiveddownlink control information, beam selection information to be fed backto the base station.

Specifically, as an exemplary implementation manner, the user equipmentmay perform downlink channel quality (for example, one or more of CQI,RSRP and RSRQ) measurement based on the non-periodic beamformedreference signal configured by the base station, and then determine beamselection information based on downlink channel quality measurementresults. In a certain embodiment, the beam selection information may berepresented in a form of bitmap. For example, it is possible to set bitscorresponding to a predetermined number (which is for example assumed tobe two herein) of measurement results magnitudes of which rank firstamong L measurement results corresponding to the L beams in the firstbeam group as 1, and to set remaining bits as 0, thereby generating abitmap X as the beam selection information.

FIG. 3 is a schematic view showing an exemplary format of the bitmap Xas an example of beam selection information according to an embodimentof the present disclosure. As shown in FIG. 3, the bitmap X comprises atotal of L bits, which are in one-to-one correspondence to the L beamsin the first beam group and reflect downlink channel quality measurementresults for the L beams. In this way, when receiving the bitmap X, thebase station can directly determine beams corresponding to bits whichare 1 therein, as candidate beams.

It can be understood that, signaling overhead can be reduced by adoptingfor example the form of bitmap as shown in FIG. 3 to feed back the beamselection information.

Alternatively, as another exemplary manner, the user equipment may alsodirectly generate downlink channel quality measurement results on the Lbeams, in a manner of being in one-to-one correspondence to the L beams,as the beam selection information, such that the base station candetermine beams corresponding to a predetermined number of downlinkchannel quality measurement results magnitudes of which rank first, asthe candidate beams, according to the received downlink channel qualitymeasurement results on the L beams.

In addition, as another example, instead of reporting the downlinkchannel quality measurement results on the L beams, the user equipmentmay also report the downlink channel quality measurement resultsmagnitudes of which rank first in association with serial numbers of thebeams corresponding thereto, as the beam selection information, to thebase station, such that the base station can directly determine thecandidate beams according to the received beam selection information.

In step S206, the base station determines one or more candidate beamsand precoding codebooks corresponding to the one or more candidatebeams, based on for example bits which are 1 in the bitmap X or based onthe downlink channel quality measurement results fed back, according tothe received beam selection information. Herein, it is assumed that thecandidate beams include beam A and beam B, such that the base stationcan determine short-term/subband feedback precoding codebooks W_(2A) andW_(2B) for the beam A and the beam B, and further determine precodingcodebooks W_(A) and W_(B) of the beam A and the beam B according to theabove determined long-term/wideband feedback precoding codebook W₁, thatis, W_(A)=W₁×W_(2A), W_(B)=W₁×W_(2B).

In step S207, the base station determines an effective precodingcodebook according to the above determined one or more precodingcodebooks (for example, the foregoing precoding codebooks W_(A) andW_(B)) corresponding to the candidate beams. For example, the basestation may determine a combination of the precoding codebooks W_(A) andW_(B) as the effective precoding codebook. Also for example, in a casewhere the beam selection information comprises downlink channel qualitymeasurement results on related beams, the base station may alsodetermine a codebook corresponding to a beam whose downlink channelquality measurement result (for example, RSRP value) is maximum, as theeffective precoding codebook.

Preferably, in step S207, besides the one or more precoding codebookscorresponding to the candidate beams, the base station determines theeffective precoding codebook based further on a precoding codebook Wdetermined according to the PMI periodically fed back.

Specifically, as an exemplary implementation manner, the base stationmay determine whether differences between the precoding codebooks (forexample, W_(A) and W_(B)) corresponding to the candidate beams and theforegoing precoding codebook W determined based on the PMI fed back areless than or equal to a predetermined threshold. If it is determinedthat a difference between any one of the precoding codebooks W_(A) andW_(B) and the precoding codebook W is less than or equal to thepredetermined threshold, it is indicated that the PMI fed back is notexpired, and accordingly, the base station may determine the precodingcodebook W as the effective precoding codebook.

On the other hand, if it is determined that differences between both theprecoding codebooks W_(A) and W_(B) and the precoding codebook W arelarger than the predetermined threshold, it is indicated that the PMIfed back is expired, making it necessary to adjust the PMI. At thistime, the base station may determine a combination of the precodingcodebooks W_(A), W_(B) and W as the effective precoding codebook.Preferably, the combination may be a linear combination.

As an example, the base station may determine, according to for examplea movement speed of the user equipment, weights assigned to theprecoding codebooks W_(A), W_(B) and W respectively when the linearcombination is performed. Alternatively, in a case where the beamselection information feeds back the specific channel qualitymeasurement results, it is also possible to determine the weights of therespective precoding codebooks according to channel quality measurementresults which correspond to the precoding codebooks W_(A) and W_(B)respectively. Of course, it is also possible to determine the weightstaking both the movement speed and the channel quality measurementresults into comprehensive consideration.

Those skilled in the art may set, according to actual requirements, theweights assigned to the respective precoding codebooks when the linearcombination is performed, and the present disclosure does not makespecific limitations to this. For example, the weights may also be setin advance. In addition, as a simple implementation manner, for example,the weights assigned to the respective precoding codebooks may also bethe same.

It should be noted that, although the example of the overall flow of thePMI adjustment solution according to the embodiment of the presentdisclosure has been described above with reference to FIG. 2, theexemplary flow shall not be construed to limit the scope of the presentdisclosure; those skilled in the art may perform modifications on theexemplary flow according to the principle of the present disclosure, andall of these modifications shall be construed to fall into the scope ofthe present disclosure. For example, the execution order of theforegoing respective steps is not limited to this, but instead, therespective steps may also be executed in parallel or independently. Alsofor example, the number of the candidate beams is also not limited totwo, but may be adjusted according to actual circumstances.

FIG. 4 is a timing sequence diagram showing an exemplary process of aPMI adjustment solution according to an embodiment of the presentdisclosure.

As shown in FIG. 4, it is assumed that, a time at which the userequipment preforms a next PMI feedback is T1, the base stationconfigures a non-periodic beamformed reference signal for the userequipment at a time T2 after receiving the request signaling from theuser equipment, and the user equipment feeds back its beam selectioninformation at a time T3 after receiving the downlink controlinformation from the base station. The timing sequence among the timesT1, T2 and T3 is: T2<T3<T1. That is, the beam selection information fedback by the user equipment according to the non-periodic beamformedreference signal may serve as a reference as to whether to adjust a PMInext fed back. Generally speaking, the user equipment may, at a nextsubframe after receipt of the non-periodic beamformed reference signal,report its downlink channel quality measurement result; thus, it ispossible to for example set as such that T3=T2+1, a time differencebetween T1 and T3 shall be less than a predetermined threshold, and thepredetermined threshold may be set in advance according to factors suchas an actual application scenario and/or a movement speed of the userequipment and the like.

Similarly, in a next feedback period, similar operations to thoseperformed at times T1, T2 and T3 are performed at times T1′, T2′ andT3′, respectively; moreover, the relationship and the setting among thetimes T1′, T2′ and T3′ also satisfy those described above for the timesT1, T2 and T3, and description will not be repeatedly made herein.

To further facilitate the understanding of the PMI adjustment solutionaccording to the embodiment of the present disclosure, furtherdescription will be made with reference to the signaling interactionflowcharts as shown in FIG. 5 and FIG. 6 below. FIG. 5 is a flowchartshowing an example of a signaling interaction process of a PMIadjustment solution according to an embodiment of the presentdisclosure. FIG. 6 is a flowchart showing another example of a signalinginteraction process of a PMI adjustment solution according to anembodiment of the present disclosure.

As shown in FIG. 5, in step S501, the base station periodicallyconfigures for example a CSI-RS for the user equipment, and in stepS502, the user equipment periodically feeds back CSI. Then, in stepS503, the user equipment evaluates that a current communication qualityis lower than a predetermined threshold, and then in step S504, sends arequest signaling to the base station, that is, R1=1, to request thebase station to configure a non-periodic beamformed CSI-RS for the userequipment. Then, in step S505, the base station configures anon-periodic beamformed CSI-RS for the user equipment based on the firstbeam group determined according to the long-term/wideband feedbackprecoding codebook W₁, and then in step S506, sends downlink controlinformation DCI format 0 (wherein, PMI_Adjust_Flag=1) to the userequipment to instruct the user equipment to feed back beam selectioninformation. In step S507, the user equipment feeds back beam selectioninformation for example in the form of a bitmap X. In step S508, thebase station determines, for example by comparing the precodingcodebooks W_(A) and W_(B) corresponding to the candidate beams with theprecoding codebook W determined according to the PMI periodically fedback, that the PMI fed back is not expired, and thereby sends theprecoding codebook W to the user equipment as the effective precodingcodebook in step S509.

It should be noted that, the execution order of the respective steps inthe flowchart as shown in FIG. 5 is not limited to that described above,and the execution order as shown aims only to facilitate description.Actually, the steps S501 and S502 of periodically configuring a CSI-RSand feeding back CSI are executed independently of but have nochronological relationship with the subsequent steps S503 and S509 ofselectively adjusting a PMI. The solution (i.e., the steps S503 throughS509) of selectively adjusting a PMI according to the present disclosureis triggered based on an event, for example, is triggered when acommunication quality of the user equipment drops and thereby fails tosatisfy a predetermined requirement.

In addition, it should also be noted that, the signaling interactionflowchart as shown in FIG. 5 is only an example given to facilitatedescription and understanding, but is not intended to limit the scope ofthe present disclosure. For example, after receiving the beam selectioninformation, the base station may also not execute the foregoing stepS508, but determines the candidate beams and the corresponding precodingcodebooks directly according to the beam selection information in stepS509, and determines the effective precoding codebook according to theprecoding codebooks corresponding to the candidate beams and sends theeffective precoding codebook to the user equipment. Also for example,the feedback manner for the beam selection information is notnecessarily the bitmap X, but may be the foregoing specific channelquality measurement results. Those skilled in the art may perform propermodifications on the signaling interaction flow according to theprinciple of the present disclosure, and all of such modifications shallbe construed to fall into the scope of the present disclosure.

The signaling interaction flow as shown in FIG. 6 is substantially thesame as the signaling interaction process as shown in FIG. 5 except fora difference in the following: in step S608, the base station determinesthat a PMI is expired, and thereby in step S609, sends a combination(preferably, a linear combination) of the precoding codebooks W_(A),W_(B) and W as the effective precoding codebook to the user equipment.Similarly, it may be understood that, the determination operation in thestep S608 may also not be executed, but instead, the effective precodingcodebook is determined directly based on a combination of W_(A) andW_(B) or a combination of W_(A), W_(B) and W.

Alternatively, as another embodiment, instead of adjusting the PMIperiodically fed back based on the beam selection information fed backby the user equipment as described above, the user equipment may alsofeed back a non-periodic PMI according to the configured non-periodicbeamformed reference signal, such that the base station can directlydetermine the effective precoding codebook based on the non-periodicPMI. The PMI adjustment solution according to the embodiment will bedescribed in detail with reference to FIG. 7.

FIG. 7 is an overall flowchart showing an exemplary process of a PMIadjustment solution according to another embodiment of the presentdisclosure.

The processing in the steps S701 through S703 as shown in FIG. 7 are thesame as the processing in the steps S201 through S203 as shown in FIG.2, and will not be repeated herein.

Next, in step S704, the base station generates downlink controlinformation to instruct the user equipment to feed back a non-periodicPMI. Specifically, similarly to the step S204, the base station may alsomodify the existing DCI format 0, to utilize a redundant bit or a newadded bit therein to instruct the user equipment to feed back anon-periodic PMI. For example, one-bit identification informationPMI_Adjust_Flag may be set, wherein if PMI_Adjust_Flag=1, it isrepresented that the base station requires the user equipment to feedback a non-periodic PMI, and otherwise if PMI_Adjust_Flag=0, it isrepresented that the base station does not require the user equipment tofeed back a non-periodic PMI. Alternatively, as another exemplaryimplementation manner, it is also possible to modify the existing RRCsignaling, to trigger the user equipment to feed back non-periodic CSI(including PMI, CQI and RI) based on a non-periodic reference signal(CSI-RS) from the base station.

Then, the solution proceeds to step S705. In the step S705, the userequipment generates a non-periodic PMI based on the configurednon-periodic beamformed reference signal and feeds back the generatedPMI to the base station.

Next, in step S706, the base station may determine a correspondingprecoding codebook W′ according to the received non-periodic PMI, andthen in step S707, determine an effective precoding codebook based onthe precoding codebook W′. As an exemplary manner, the base station maydirectly determine the precoding codebook W′ as the effective precodingcodebook. Alternatively, the base station may also determine acombination of the precoding codebook W′ and the precoding codebook Wdetermined according to the PMI periodically fed back, as the effectiveprecoding codebook. The combination for example may be a linearcombination.

The embodiment mainly describes the difference from the foregoing PMIadjustment solution based on beam selection information. For othersimilar contents, reference may be made to the foregoing correspondingdescription, and description will not be repeatedly made herein.

It should be noted that, although the two embodiments of performing PMIadjustment based on the beam selection information fed back by the userequipment and performing PMI adjustment based on the non-periodic PMIfed back by the user equipment have been separately described above, inactual implementation those skilled in the art may also combine theforegoing two embodiments according to the principle of the presentdisclosure. For example, when generating downlink control information toinstruct the user equipment to feed back information, the base stationmay make an instruction by utilizing a two-bit redundant bit or newadded bit in the existing DCI format 0. For example, as an exemplarymanner, two-bit identification information PMI_Adjust_Flag may be set,wherein if PMI_Adjust_Flag=00, it is represented that the user equipmentis not required to perform a feedback; if PMI_Adjust_Flag=10, it isrepresented that the user equipment is required to feed back beamselection information; and if PMI_Adjust_Flag=11, it is represented thatthe user equipment is required to feed back a non-periodic PMI. In thisway, the user equipment may perform proper information feedbackaccording to the received downlink control information, such that thebase station can adopt a proper PMI adjustment solution according to thereceived feedback information.

According to the foregoing embodiment of the present disclosure, besidesperiodically configuring a reference signal like in the prior art, thebase station is also selectively triggered, according to a communicationquality of the user equipment, to configure a non-periodic beamformedreference signal for the user equipment so as to determine, according tothe beam selection information or the non-periodic PMI fed back by theuser equipment based on the non-periodic beamformed reference signal,whether it is necessary to perform adjustment on the PMI periodicallyfed back, thereby avoiding the problems of precoding mismatching andcommunication quality deterioration of the user equipment which arecaused by an expired PMI in a high speed scenario.

In correspondence to the PMI adjustment solutions according to theembodiments of the present disclosure as described above, configurationsat base station end and user equipment end in a wireless communicationsystem according to embodiments of the present disclosure will bedescribed with FIG. 8 through 10 below.

FIG. 8 is a block diagram showing a function configuration example of anelectronic device at base station end in a wireless communication systemaccording to an embodiment of the present disclosure.

As shown in FIG. 8, an electronic device 800 according to the embodimentmay comprise a reference signal configuration unit 802, a downlinkcontrol information generation unit 804, an adjustment codebookdetermination unit 806 and an effective codebook determination unit 808.

It should be noted that, each unit described herein is only a logicfunction module divided according to the specific function implementedby the unit, but is not used to limit a specific implementation manner.In actual implementation, said each function unit may be realized as anindependent physical entity, or may also be realized by a single entity(e.g., a processor (a CPU or a DSP or the like), an integrated circuit,etc.).

The reference signal configuration unit 802 may be configured toconfigure, in response to a request signaling from a user equipment, anon-periodic beamformed reference signal related to a first beam groupfor the user equipment. The first beam group is determined by the basestation according to channel state information periodically fed back bythe user equipment.

Preferably, the reference signal configuration unit 802 may be furtherconfigured to configure a periodic reference signal for the userequipment, and to determine the first beam group according to thechannel state information fed back by the user equipment in response tothe periodic reference signal. The periodic reference signal may benon-precoded or beamformed.

Specifically, as described above, the reference signal configurationunit 802 determines a long-term/wideband feedback precoding codebook W₁based on the PMI in the CSI periodically fed back by the user equipment,and determines the first beam group based on the long-term/widebandfeedback precoding codebook W₁, thereby configuring a non-periodicbeamformed reference signal for the user equipment based on the firstbeam group. The foregoing reference signal comprises for example CSI-RS.

The downlink control information generation unit 804 may be configuredto generate downlink control information to instruct the user equipmentto feed back beam selection information according to the non-periodicbeamformed reference signal.

Preferably, the control information generation unit 804 may modify theexisting DCI format 0, to utilize a redundant bit or a new added bittherein as PMI_Adjust_Flag to instruct the user equipment to feed backbeam selection information.

The adjustment codebook determination unit 806 may be configured todetermine one or more candidate beams and one or more precodingcodebooks corresponding to the one or more candidate beams according tothe beam selection information fed back by the user equipment.

Specifically, the adjustment codebook determination unit 806 maydetermine the one or more candidate beams according to bit informationindicating a downlink channel quality measurement result based on thenon-periodic beamformed reference signal in the beam selectioninformation in a form of bitmap. For example, beams corresponding tobits which are 1 in the bitmap X may be determined as the one or morecandidate beams. Alternatively, the adjustment codebook determinationunit 806 may also determine beams corresponding to a predeterminednumber of downlink channel quality measurement results magnitudes ofwhich rank first, as the one or more candidate beams, according to thedownlink channel quality measurement result based on the non-periodicbeamformed reference signal which is fed back by the user equipment.Then, the adjustment codebook determination unit 806 may determine oneor more second precoding codebooks corresponding to the one or morecandidate beams, for example, the foregoing precoding codebooks W_(A)and W_(B). For the specific process of determining the second precodingcodebooks, reference may be made to the foregoing description, anddescription will not be repeatedly made herein.

The effective codebook determination unit 808 may be configured todetermine an effective precoding codebook based on the determined one ormore second precoding codebooks (for example, the foregoing precodingcodebooks W_(A) and W_(B)). For example, the effective codebookdetermination unit 808 may determine a combination of W_(A) and W_(B) asthe effective precoding codebook. Alternatively, the effective codebookdetermination unit 808 may determine one of W_(A) and W_(B) as theeffective precoding codebook according to the channel qualitymeasurement result.

Preferably, besides the one or more second precoding codebookscorresponding to the candidate beams, the effective codebookdetermination unit 808 determines the effective precoding codebook basedfurther on a first precoding codebook (for example, the foregoingprecoding codebook W) which is determined according to the channel stateinformation periodically fed back.

Specifically, as an exemplary implementation, the effective codebookdetermination unit 808 may be configured to determine, if a differencebetween any one of the one or more second precoding codebooks and thefirst precoding codebook is less than or equal to a predeterminedthreshold, the first precoding codebook as the effective precodingcodebook W_(E), that is, W_(E)=W. On the other hand, the effectivecodebook determination unit 808 may determine, if the difference betweeneach of the one or more second precoding codebooks and the firstprecoding codebook is larger than the predetermined threshold, acombination (preferably, a linear combination) of the first precodingcodebook and the one or more second precoding codebooks as the effectiveprecoding codebook, for example, W_(E)=aW+bW_(A)+cW_(B). The weightvalues a, b and c may be determined in advance, or may also bedetermined by the effective codebook determination unit 808 according toa movement speed of the user equipment and/or beam selection information(specifically, an amplitude of the downlink channel quality measurementresult based on the non-periodic beamformed reference signal which isfed back by the user equipment).

FIG. 9 is a block diagram showing a function configuration example of anelectronic device at base station end in a wireless communication systemaccording to another embodiment of the present disclosure.

As shown in FIG. 9, an electronic device 900 according to the embodimentmay comprise a reference signal configuration unit 902 and a downlinkcontrol information generation unit 904.

It should be noted that, each unit described herein is only a logicfunction module divided according to the specific function implementedby the unit, but is not used to limit a specific implementation manner.In actual implementation, said each function unit may be realized as anindependent physical entity, or may also be realized by a single entity(e.g., a processor (a CPU or a DSP or the like), an integrated circuit,etc.).

The reference signal configuration unit 902 may be configured toconfigure, in response to a request signaling from a user equipment, anon-periodic beamformed reference signal related to a first beam groupfor the user equipment, the first beam group being determined by thebase station according to channel state information periodically fedback by the user equipment.

The downlink control information generation unit 904 may be configuredto generate downlink control information to instruct the user equipmentto feed back a non-periodic PMI according to the non-periodic beamformedreference signal.

Preferably, the electronic device 900 may further comprise a codebookdetermination unit, which may be configured to determine a correspondingsecond precoding codebook according to the received non-periodic PMI,and to further determine an effective precoding codebook based on thesecond precoding codebook. For example, the codebook determination unitmay directly determine the second precoding codebook as the effectiveprecoding codebook.

Preferably, besides the second precoding codebook, the codebookdetermination unit determines the effective precoding codebook basedfurther on a first precoding codebook which is determined according tothe PMI periodically fed back. For example, a combination (for example,a linear combination) of the second precoding codebook and the firstprecoding codebook may be determined as the effective precodingcodebook.

It should be noted that the foregoing electronic devices 800 and 900 maybe realized in chip level or may also be realized in device level byincluding other external components. For example, the electronic devices800 and 900 each may as a whole operate as a base station, which mayinclude a communication interface for performing transceivingoperations, for example, receiving a request signaling from the userequipment, sending a non-periodic beamformed reference signal anddownlink control information to the user equipment, receiving beamselection information or a non-periodic PMI from the user equipment, andsending a determined effective precoding codebook to the user equipment,and the like.

FIG. 10 is a block diagram showing a function configuration example ofan electronic device at user equipment end in a wireless communicationsystem according to an embodiment of the present disclosure.

As shown in FIG. 10, an electronic device 1000 according to the presentembodiment may comprise an evaluation unit 1002, a request unit 1004 anda generation unit 1006.

It should be noted that, each unit described herein is only a logicfunction module divided according to the specific function implementedby the unit, but is not used to limit a specific implementation manner.In actual implementation, said each function unit may be realized as anindependent physical entity, or may also be realized by a single entity(e.g., a processor (a CPU or a DSP or the like), an integrated circuit,etc.).

The evaluation unit 1002 may be configured to evaluate a communicationquality between the user equipment and a base station, to determinewhether the communication quality is lower than a predeterminedthreshold. The operation for example may be periodically performed.

The request unit 1004 may be configured to generate, in a case where theevaluation unit 1002 determines that the communication quality is lowerthan the predetermined threshold, a request signaling to request thebase station to configure a non-periodic beamformed reference signalrelated to a first beam group for the user equipment. The first beamgroup is determined by the base station according to channel stateinformation periodically fed back by the user equipment. For thespecific determination process, reference may be made to the foregoingdescription, and description will not be repeatedly made herein.

The generation unit 1006 may be configured to generate, in response todownlink control information from the base station, beam selectioninformation according to the non-periodic beamformed reference signal,for the base station to determine an effective precoding codebook basedon the beam selection information.

Specifically, the information generation unit 1006 may be configured togenerate the beam selection information in a form of bitmap, accordingto a downlink channel quality measurement result based on thenon-periodic beamformed reference signal, in response to a redundant bitor a new added bit (PMI_Adjust_Flag=1) in the DCI format 0. For example,bits corresponding to a predetermined number of downlink channel qualitymeasurement results magnitudes of which rank first among the measurementresults are set as 1, and remaining bits are set as 0, therebygenerating the foregoing bitmap X as the beam selection information.Alternatively, the information generation unit 1006 may also directlygenerate a downlink channel quality measurement result based on thenon-periodic beamformed reference signal, as the beam selectioninformation. The beam selection information is in one-to-onecorrespondence to the beams in the first beam group.

Preferably, the information generation unit 1006 may be furtherconfigured to generate, in response to a periodic reference signal(either precoded or beamformed) from the base station, the channel stateinformation to be periodically fed back.

FIG. 11 is a block diagram showing a function configuration example ofan electronic device at user equipment end in a wireless communicationsystem according to another embodiment of the present disclosure.

As shown in FIG. 11, an electronic device 1100 according to theembodiment may comprise an evaluation unit 1102 and a request unit 1104.

It should be noted that, each unit described herein is only a logicfunction module divided according to the specific function implementedby the unit, but is not used to limit a specific implementation manner.In actual implementation, said each function unit may be realized as anindependent physical entity, or may also be realized by a single entity(e.g., a processor (a CPU or a DSP or the like), an integrated circuit,etc.).

The function configuration examples of the evaluation unit 1102 and therequest unit 1104 herein are the same as the function configurationexamples of the evaluation unit 1002 and the request unit 1004 asdescribed above with reference to FIG. 10, and will not be repeatedlydescribed herein.

Preferably, the electronic device 1100 may further comprise a generationunit, which may be configured to generate, in response to downlinkcontrol information from the base station, a non-periodic PrecodingMatrix Indicator to be sent to the base station according to thenon-periodic beamformed reference signal, for the base station todetermine an effective precoding codebook based on the non-periodicPrecoding Matrix Indicator.

It should be understood that the foregoing electronic devices 1000 and1100 may be realized in chip level or may also be realized in devicelevel by including other external components. For example, theelectronic devices 1000 and 1100 each may as a whole operate as a userequipment, which may include a communication interface for performingtransceiving operations, for example, sending a request signaling to thebase station, receiving a periodic reference signal and a non-periodicbeamformed reference signal and downlink control information from thebase station, sending channel state information and beam selectioninformation or a non-periodic PMI to the base station, and receiving aneffective precoding codebook from the base station, and the like.

It should be noted that, the configurations of the electronic devices800 and 900 at base station end and the electronic devices 1000 and 1100at user equipment end as described herein correspond to the PMIadjustment solutions as described above with reference to FIG. 2 throughFIG. 7. Thus, for contents not described in detail herein, reference maybe made to the foregoing corresponding description, and no repeateddescription will be made herein.

In addition, it should also be noted that, although the functionconfigurations of the electronic devices 800 through 1100 have beendescribed above with reference to FIG. 8 through FIG. 11, this is onlyexemplary but not limiting, and those skilled in the art may carry outmodifications on the above function configurations, for example carryout deletions, combinations, sub-combinations and alternations and thelike on the above function modules, according to the principle of thepresent disclosure and actual circumstances. Moreover, all of suchmodifications shall be construed to fall within the scope of the presentdisclosure.

FIG. 12 is a block diagram showing a configuration example of a wirelesscommunication system according to an embodiment of the presentdisclosure.

As shown in FIG. 12, a wireless communication system 1200 according tothe embodiment may comprise a base station 1210 and a user equipment1220.

The base station 1210 may comprise a processing circuitry 1211 and acommunication interface 1212.

The processing circuitry 1211 may be configured to implement thefunctions of the respective units of the electronic devices 800 and 900at base station end as described above with reference to FIG. 8 and FIG.9. The specific implementation manner of the processing circuitry 1211may include a CPU, a DSP, a dedicated integrated circuit and the like.

The communication interface 1212 may be configured to performtransceiving operations between the base station and the user equipment.

The user equipment 1220 may comprise a processing circuitry 1221 and acommunication interface 1222.

The processing circuitry 1221 may be configured to implement thefunctions of the respective units of the electronic devices 1000 and1100 at user equipment end as described above with reference to FIG. 10and FIG. 11. The specific implementation manner of the processingcircuitry 1221 may include a CPU, a DSP, a dedicated integrated circuitand the like.

The communication interface 1222 may be configured to performtransceiving operations between the user equipment and the base station.

In correspondence to the foregoing device embodiments, the presentdisclosure further provides the following method embodiments.

FIG. 13 is a flowchart showing a process example of a method at basestation end in a wireless communication system according to anembodiment of the present disclosure.

As shown in FIG. 13, a method 1300 according to the embodiment startsfrom step S1301. In the step S1301, a non-periodic beamformed referencesignal related to a first beam group is configured for the userequipment in response to a request signaling from a user equipment, thefirst beam group being determined by the base station according tochannel state information periodically fed back by the user equipment.

Then, the method proceeds to step S1302. In the step S1302, downlinkcontrol information is generated to instruct the user equipment to feedback beam selection information according to the non-periodic beamformedreference signal.

Next, the method proceeds to step S1303. In the step S1303, one or morecandidate beams and one or more second precoding codebooks correspondingto the one or more candidate beams are determined according to the beamselection information.

Finally, in step S1304, an effective precoding codebook is determinedbased on the one or more second precoding codebooks.

Preferably, in the step S1304, the effective precoding codebook isdetermined based further on a first precoding codebook which isdetermined according to the channel state information periodically fedback.

FIG. 14 is a flowchart showing a process example of a method at basestation end in a wireless communication system according to anotherembodiment of the present disclosure.

As shown in FIG. 14, a method 1400 according to the embodiment startsfrom step S1401. In the step S1401, a non-periodic beamformed referencesignal related to a first beam group is configured for the userequipment in response to a request signaling from a user equipment, thefirst beam group being determined by the base station according tochannel state information periodically fed back by the user equipment.

Then, the method proceeds to step S1402. In the step S1402, downlinkcontrol information is generated to instruct the user equipment to feedback a non-periodic PMI according to the non-periodic beamformedreference signal.

Preferably, the method may further comprise the step of: determining asecond precoding codebook according to the non-periodic PMI, and furtherdetermining an effective precoding codebook according to the secondprecoding codebook. Preferably, the effective precoding codebook mayalso be determined based on a combination of the second precodingcodebook and a first precoding codebook which is determined according tothe PMI periodically fed back.

It should be noted that, the method embodiments as shown in FIGS. 13 and14 correspond to the embodiments of the electronic devices at basestation end as described above with reference to FIG. 8 and FIG. 9.Thus, for contents not described in detail herein, reference may be madeto the foregoing corresponding description, and no repeated descriptionwill be made herein.

FIG. 15 is a flowchart showing a process example of a method at userequipment end in a wireless communication system according to anembodiment of the present disclosure.

As shown in FIG. 15, the method starts from step S1501. In the stepS1501, it is determined whether a communication quality between the userequipment and a base station is lower than a predetermined threshold.

Then, the method proceeds to step S1502. In the step S1502, in a casewhere it is determined that the communication quality is lower than thepredetermined threshold, a request signaling to be sent to the basestation is generated, to request the base station to configure anon-periodic beamformed reference signal related to a first beam groupfor the user equipment, the first beam group being determined by thebase station according to channel state information periodically fedback by the user equipment.

Next, the method proceeds to step S1503. In the step S1503, beamselection information to be sent to the base station is generatedaccording to the non-periodic beamformed reference signal in response todownlink control information from the base station, for the base stationto determine an effective precoding codebook based on the beam selectioninformation.

FIG. 16 is a flowchart showing a process example of a method at userequipment end in a wireless communication system according to anotherembodiment of the present disclosure.

As shown in FIG. 16, the method starts from step S1601. In the stepS1601, it is determined whether a communication quality between the userequipment and a base station is lower than a predetermined threshold.

Then, the method proceeds to step S1602. In the step S1602, in a casewhere it is determined that the communication quality is lower than thepredetermined threshold, a request signaling to be sent to the basestation is generated, to request the base station to configure anon-periodic beamformed reference signal related to a first beam groupfor the user equipment, the first beam group being determined by thebase station according to channel state information periodically fedback by the user equipment.

Preferably, the method may further comprise the step of: generating, inresponse to downlink control information from the base station, anon-periodic PMI to be sent to the base station according to thenon-periodic beamformed reference signal, for the base station todetermine an effective precoding codebook based on the non-periodic PMI.

It should be noted that, the method embodiments as shown in FIGS. 15 and16 correspond to the embodiments of the electronic devices at userequipment end as described above with reference to FIG. 10 and FIG. 11.Thus, for contents not described in detail herein, reference may be madeto the foregoing corresponding description, and no repeated descriptionwill be made herein.

It should be understood that, the machine executable instructions in thestorage medium and the program product according to the embodiments ofthe present disclosure may be further configured to implement themethods corresponding to the foregoing device embodiments. Thus forcontents not described in detail herein, reference may be made to theforegoing corresponding description, and no repeated description will bemade herein.

Accordingly, a storage medium for carrying the above program productcomprising machine executable instructions is also included in thedisclosure of the present invention. The storage medium includes but isnot limited to a floppy disc, an optical disc, a magnetic optical disc,a memory card, a memory stick and the like.

In addition, it should also be noted that, the foregoing series ofprocessing and devices may also be implemented by software and/orfirmware. In the case of implementation by software and/or firmware,programs constituting the software are installed from a storage mediumor a network to a computer having a dedicated hardware structure, forexample the universal personal computer 1700 as shown in FIG. 17. Thecomputer, when installed with various programs, can execute variousfunctions and the like. FIG. 17 is a block diagram showing an exemplarystructure of a personal computer as an information processing deviceusable in an embodiment of the disclosure.

In FIG. 17, a Central Processing Unit (CPU) 1701 executes variousprocessing according to programs stored in a Read-Only Memory (ROM) 1702or programs loaded from a storage part 1708 to a Random Access Memory(RAM) 1703. In the RAM 1703, data needed when the CPU 1701 executesvarious processing and the like is also stored according torequirements.

The CPU 1701, the ROM 1702 and the RAM 1703 are connected to each othervia a bus 1704. An input/output interface 1705 is also connected to thebus 1704.

The following components are connected to the input/output interface1705: an input part 1706, including a keyboard, a mouse and the like; anoutput part 1707, including a display, such as a Cathode Ray Tube (CRT),a Liquid Crystal Display (LCD) and the like, as well as a speaker andthe like; the storage part 1708, including a hard disc and the like; anda communication part 1709, including a network interface card such as anLAN card, a modem and the like. The communication part 1709 executescommunication processing via a network such as the Internet.

According to requirements, a driver 1710 is also connected to theinput/output interface 1705. A detachable medium 1711 such as a magneticdisc, an optical disc, a magnetic optical disc, a semiconductor memoryand the like is installed on the driver 1710 according to requirements,such that computer programs read therefrom are installed in the storagepart 1708 according to requirements.

In a case where the foregoing series of processing is implemented bysoftware, programs constituting the software are installed from anetwork such as the Internet or a storage medium such as the detachablemedium 1711.

Those skilled in the art should appreciate that, such a storage mediumis not limited to the detachable medium 1711 in which programs arestored and which are distributed separately from an apparatus to providethe programs to users as shown in FIG. 17. Examples of the detachablemedium 1711 include a magnetic disc (including a floppy disc (registeredtrademark)), a compact disc (including a Compact Disc Read-Only Memory(CD-ROM) and a Digital Versatile Disc (DVD), a magneto optical disc(including a Mini Disc (MD) (registered trademark)), and a semiconductormemory. Or, the memory medium may be hard discs included in the ROM 1702and the memory part 1708, in which programs are stored and which aredistributed together with the apparatus containing them to users.

APPLICATION EXAMPLES

The technology of the present disclosure can be applied to variousproducts, including a base station and a user equipment. Specifically,the base station may be realized as any type of evolutional node B(eNB), such as macro eNB and small eNB. The small eNB may be an eNB of acell with smaller coverage than a macro cell, such as a pico eNB, amicro eNB and a home (femto) eNB. Alternatively, the base station may berealized as any other type of base station, such as NodeB and BaseTransceiver Station (BTS). The base station may comprise: a main body(also called base station equipment) configured to control wirelesscommunication; and one or more Remote Radio Heads (RRHs) arranged at adifferent place from the main body. In addition, all the various typesof terminals which will be described below can operate as base stationsby temporarily or semi-persistently executing base station functions.

The user equipment may be realized as a mobile terminal (such as anintelligent telephone, a tablet Personal Computer (PC), a notebook PC, aportable game terminal, a portable/softdog mobile router and a digitalimage pick-up device) or an in-vehicle terminal (such as an automobilenavigation device). The user equipment may also be realized as aterminal for executing Machine-to-Machine (M2M) communication (alsocalled a Machine Type Communication (MTC) terminal). In addition, theuser equipment may be a wireless communication module (such as anintegrated circuit module including a single wafer) installed on each ofthe above terminals.

Hereinafter, application examples according to the present disclosurewill be described with reference to FIG. 18 through FIG. 21 below.

Application Examples Regarding Base Station First Application Example

FIG. 18 is a block diagram showing a first example of schematicconfiguration of an eNB to which the technology according to the presentdisclosure can be applied. The eNB 1800 comprises one or more antennas1810 and base station equipment 1820. The base station equipment 1820and each antenna 1810 may be connected to each other via an RF cable.

Each of the antennas 1810 comprises a single or more antenna elements(such as a plurality of antenna elements included in a Multi-InputMulti-Output (MIMO) antenna), and is used for the base station equipment1820 to transmit and receive a wireless signal. As shown in FIG. 18, theeNB 1800 may comprise a plurality of antennas 1810. For example, theplurality of antennas 1810 may be compatible with a plurality offrequency bands used by the eNB 1800. Although FIG. 18 shows an examplein which the eNB 1800 comprises a plurality of antennas 1810, the eNB1800 may also comprise a single antenna 1810.

The base station equipment 1820 may comprise a controller 1821, a memory1822, a network interface 1823, and a wireless communication interface1825.

The controller 1821 may be for example a CPU or a DSP, and manipulatevarious functions of a higher layer of the base station equipment 1820.For example, the controller 1821 generates data packets according todata in a signal processed by the wireless communication interface 1825,and transfers the generated packets via the network interface 1823. Thecontroller 1821 may perform binding for data from a plurality ofbaseband processors to generate bound packets, and transfer thegenerated bound packets. The controller 1821 may have a logic functionof executing control, which is such as radio resource control, radiobearer control, mobility management, admission rule and scheduling. Thecontrol may be executed in combination with a nearby eNB or a corenetwork node. The memory 1822 comprises an RAM and an ROM, and storesprograms executed by the controller 1821 and various types of controldata (such as a terminal list, transmission power data, and schedulingdata).

The network interface 1823 is a communication interface for connectingthe base station equipment 1820 to a core network 1824. The controller1821 may communicate with a core network node or another eNB via thenetwork interface 1823. In this case, the eNB 1800 and the core networknode or another eNB may be connected to each other via a logic interface(such as S1 interface and X2 interface). The network interface 1823 mayalso be a wired communication interface, or a wireless communicationinterface for a wireless backhaul. If the network interface 1823 is awired communication interface, as compared with frequency bands used bythe wireless communication interface 1825, the network interface 1823may use higher frequency bands for wireless communication.

The wireless communication interface 1825 supports any cellularcommunication scheme (such as Long Term Evolution (LTE) andLTE-Advanced), and is provided with a wireless connection to a terminallocated in a cell of the eNB 1800 via the antenna 1810. The wirelesscommunication interface 1825 generally may comprise for example aBaseBand (BB) processor 1826 and an RF circuit 1827. The BB processor1826 may execute for example coding/decoding, modulation/demodulationand multiplexing/demultiplexing, and execute various types of signalprocessing of layers (for example L1, Medium Access control (MAC), RadioLink Control (RLC) and Packet Data Convergence Protocol (PDCP)). Insteadof the controller 1821, the BB processor 1826 may have part of all ofthe above logic function. The BB processor 1826 may be a memory whichstores a communication control program, or a module comprising aprocessor configured to execute a program and a related circuit. Thefunction of the BB processor 1826 may be changed through programupdating. The module may be a card or blade inserted in a slot of thebase station equipment 1820. Alternatively, the module may also be achip installed on a card or blade. Meanwhile, the RF circuit 1827 maycomprise for example a frequency mixer, a filter and an amplifier, andtransmit and receive a wireless signal via the antenna 1810.

As shown in FIG. 18, the wireless communication interface 1825 maycomprise a plurality of BB processors 1826. For example, the pluralityof BB processors 1826 may be compatible with a plurality of frequencybands used by the eNB 1800. As shown in FIG. 18, the wirelesscommunication interface 1825 may comprise a plurality of RF circuits1827. For example, the plurality of RF circuits 1827 may be compatiblewith a plurality of antenna elements. Although FIG. 18 shows an examplein which the wireless communication interface 1825 comprises a pluralityof BB processors 1826 and a plurality of RF circuits 1827, the wirelesscommunication interface 1825 may also comprise a single BB processor1826 or a single RF circuit 1827.

Second Application Example

FIG. 19 is a block diagram showing a second example of schematicconfiguration of an eNB to which the technology according to the presentdisclosure can be applied. The eNB 1930 comprises a plurality ofantennas 1940, base station equipment 1950, and an RRH 1960. The RRH1960 and each antenna 1940 may be connected to each other via an RFcable. The base station equipment 1950 and the RRH 1960 may be connectedto each other via a high-speed line such as an optical fiber cable.

Each of the antennas 1940 comprises a single or more antenna elements(such as a plurality of antenna elements included in an MIMO antenna)and is used for the RRH 1960 to transmit and receive a wireless signal.As shown in FIG. 19, the eNB 1930 may comprise a plurality of antennas1940. For example, the plurality of antennas 1940 may be compatible witha plurality of frequency bands used by the eNB 1930. Although FIG. 19shows an example in which the eNB 1930 comprises a plurality of antennas1940, the eNB 1930 may also comprise a single antenna 1940.

The base station equipment 1950 comprises a controller 1951, a memory1952, a network interface 1953, a wireless communication interface 1955,and a connection interface 1957. The controller 1951, the memory 1952and the network interface 1953 are the same as the controller 1821, thememory 1822 and the network interface 1823 described with reference toFIG. 18.

The wireless communication interface 1955 supports any cellularcommunication scheme (such as LTE and LTE-Advanced), and is providedwith a wireless connection to a terminal located in a sectorcorresponding to the RRH 1960 via the RRH 1960 and the antenna 1940. Thewireless communication interface 1955 generally may comprise for examplea BB processor 1956. The BB processor 1956 is the same as the BBprocessor 1826 described with reference to FIG. 18, except for that theBB processor 1956 is connected to the RF circuit 1964 of the RRH 1960via the connection interface 1957. As shown in FIG. 19, the wirelesscommunication interface 1955 may comprise a plurality of BB processors1956. For example, the plurality of BB processors 1956 may be compatiblewith a plurality of frequency bands used by the eNB 1930. Although FIG.19 shows an example in which the wireless communication interface 1955comprises a plurality of BB processors 1956, the wireless communicationinterface 1955 may also comprise a single BB processor 1956.

The connection interface 1957 is an interface for connecting the basestation equipment 1950 (the wireless communication interface 1955) tothe RRH 1960. The connection interface 1957 may also be a communicationmodule for communication in the above high-speed line for connecting thebase station equipment 1950 (the wireless communication interface 1955)to the RRH 1960.

The RRH 1960 comprises a connection interface 1961 and a wirelesscommunication interface 1963.

The connection interface 1961 is an interface for connecting the RRH1960 (the wireless communication interface 1963) to the base stationequipment 1950. The connection interface 1961 may also be acommunication module for communication in the above high-speed line.

The wireless communication interface 1963 transmits and receives awireless signal via the antenna 1940. The wireless communicationinterface 1963 generally may comprise for example an RF circuit 1964.The RF circuit 1964 may comprise for example a frequency mixer, a filterand an amplifier, and transmit and receive a wireless signal via theantenna 1940. As shown in FIG. 19, the wireless communication interface1963 may comprise a plurality of RF circuits 1964. For example, theplurality of RF circuits 1964 may support a plurality of antennaelements. Although FIG. 19 shows an example in which the wirelesscommunication interface 1963 comprises a plurality of RF circuits 1964,the wireless communication interface 1963 may also comprise a single RFcircuit 1964.

In the eNB 1800 and the eNB 1930 as shown in FIG. 18 and FIG. 19, thecommunication interfaces in the foregoing electronic devices 800 and 900may be realized by the wireless communication interface 1825 and thewireless communication interface 1955 and/or the wireless communicationinterface 1963. At least part of the functions of the reference signalconfiguration unit, the downlink control information generation unit,the codebook determining unit and the like may also be implemented bythe controller 1821 and the controller 1951.

Application Examples Regarding User Equipment First Application Example

FIG. 20 is a block diagram showing an example of schematic configurationof an intelligent telephone 2000 to which the technology according tothe disclosure can be applied. The intelligent telephone 2000 comprisesa processor 2001, a memory 2002, a storage device 2003, an externalconnection interface 2004, an image-pick up device 2006, a sensor 2007,a microphone 2008, an input device 2009, a display device 2010, aspeaker 2011, a wireless communication interface 2012, one or moreantenna switches 2015, one or more antennas 2016, a bus 2017, a battery2018, and an auxiliary controller 2019.

The processor 2001 may be for example a CPU or a System on Chip (SoC),and control functions of an application layer and additional layers ofthe intelligent telephone 2000. The memory 2002 comprises an RAM and anROM, and stores data and programs executed by the processor 2001. Thestorage device 2003 may comprise a storage medium, such as asemiconductor memory and a hard disc. The external connection interface2004 is used for connecting an external device (such as a memory cardand a Universal Serial Bus (USB) device) to an interface of theintelligent telephone 2000.

The image pick-up device 2006 comprises an image sensor (such as aCharge Coupled Device (CCD) and a Complementary Metal OxideSemiconductor (CMOS)), and generates a captured image. The sensor 2007may comprise a group of sensors, such as a measurement sensor, a gyrosensor, a geomagnetic sensor and an acceleration sensor. The microphone2008 converts sound inputted to the intelligent telephone 2000 to anaudio signal. The input device 2009 comprises for example a touch sensorconfigured to detect a touch on a screen of the display device 2010, akeypad, a keyboard, buttons or switches, and receives an operation orinformation inputted from a user. The display device 2010 comprises ascreen (such as a Liquid Crystal Display (LCD) and an OrganicLight-Emitting Diode (OLED) display), and displays an output image ofthe intelligent telephone 2000. The speaker 2011 converts the audiosignal outputted from the intelligent telephone 2000 to sound.

The wireless communication interface 2012 supports any cellularcommunication scheme (such as LTE and LTE-Advanced), and executeswireless communication. The wireless communication interface 2012generally may comprise for example a BB processor 2013 and an RF circuit2014. The BB processor 2013 may execute for example coding/decoding,modulation/demodulation and multiplexing/demultiplexing, and executevarious types of signal processing for wireless communication.Meanwhile, the RF circuit 2014 may comprise for example a frequencymixer, a filter and an amplifier, and transmit and receive a wirelesssignal via the antenna 2016. The wireless communication interface 2012may be a chip module on which a BB processor 2013 and an RF circuit 2014are integrated. As shown in FIG. 20, the wireless communicationinterface 2012 may comprise a plurality of BB processors 2013 and aplurality of RF circuits 2014. Although FIG. 20 shows an example inwhich the wireless communication interface 2012 comprises a plurality ofBB processors 2013 and a plurality of RF circuits 2014, the wirelesscommunication interface 2012 may also comprise a single BB processor2013 or a single RF circuit 2014.

In addition, besides the cellular communication schemes, the wirelesscommunication interface 2012 may support other types of wirelesscommunication schemes, such as a Device-to-Device (D2D) communicationscheme, a short range wireless communication scheme, a near fieldcommunication scheme and a wireless Local Area Network (LAN) scheme. Inthis case, the wireless communication interface 2012 may comprise a BBprocessor 2013 and an RF circuit 2014 for each wireless communicationscheme.

Each of the antenna switches 2015 switches a connection destination ofthe antenna 2016 between a plurality of circuits included in thewireless communication interface 2012 (for example, circuits fordifferent wireless communication schemes).

Each of the antennas 2016 comprises a single or more antenna elements(such as a plurality of antenna elements included in an MIMO antenna),and is used for the communication interface 2012 to transmit and receivea wireless signal. As shown in FIG. 20, the intelligent telephone 2000may comprise a plurality of antennas 2016. Although FIG. 20 shows anexample in which the intelligent telephone 2000 comprises a plurality ofantennas 2016, the intelligent telephone 2000 may also comprise a singleantenna 2016.

In addition, the intelligent telephone 2000 may comprise an antenna 2016for each wireless communication scheme. In this case, the antenna switch2015 may be omitted from the configuration of the intelligent telephone2000.

The bus 2017 connects the processor 2001, the memory 2002, the storagedevice 2003, the external connection interface 2004, the image pick-updevice 2006, the sensor 2007, the microphone 2008, the input device2009, the display device 2010, the speaker 2011, the wirelesscommunication interface 2012 and the auxiliary controller 2019 to eachother. The battery 2018 supplies electric power to the respective blocksof the intelligent telephone 2000 as shown in FIG. 20 via feeder lineswhich are partially shown as dashed lines in the figure. The auxiliarycontroller 2019 for example manipulates the least necessary function ofthe intelligent telephone 2000 in a sleep mode.

In the intelligent telephone 2000 as shown in FIG. 20, the communicationinterfaces in the foregoing electronic devices 1000 and 1100 may berealized by the wireless communication interface 2012. At least part ofthe functions of the evaluation unit, the request unit and thegeneration unit may also be implemented by the processor 2001 or theauxiliary controller 2019.

Second Application Example

FIG. 21 is a block diagram showing an example of schematic configurationof an automobile navigation device 2120 to which the technologyaccording to the present disclosure can be applied. The automobilenavigation device 2120 comprises a processor 2121, a memory 2122, aGlobal Positioning system (GPS) module 2124, a sensor 2125, a datainterference 2126, a content player 2127, a storage medium interface2128, an input device 2129, a display device 2130, a speaker 2131, awireless communication interface 2133, one or more antenna switches2136, one or more antennas 2137, and a battery 2138.

The processor 2121 may be for example a CPU or a SoC, and controls anavigation function and additional functions of the automobilenavigation device 2120. The memory 2122 comprises an RAM and an ROM, andstores data and programs executed by the processor 2121.

The GPS module 2124 measures a position (such as longitude, latitude andheight) of the automobile navigation device 2120 by using a GPS signalreceived from a GPS satellite. The sensor 2125 may comprise a group ofsensors, such as a gyro sensor, a geomagnetic sensor and an air pressuresensor. The data interface 2126 is connected to for example anin-vehicle network 2141 via a terminal which is not shown, and acquiresdata (such as vehicle speed data) generated by a vehicle.

The content player 2127 reproduces content stored in a storage medium(such as a CD and a DCD). The storage medium is inserted in the storagemedium interface 2128. The input device 2129 comprises for example atouch sensor configured to detect a touch on a screen of the displaydevice 2130, buttons or switches, and receives an operation orinformation inputted from a user. The display device 2130 comprises ascreen such as an LCD or an OLED display, and displays an image of thenavigation function or the reproduced content. The speaker 2131 outputssound of the navigation function or the reproduced content.

The wireless communication interface 2133 supports any cellularcommunication scheme (such as LTE and LTE-Advanced), and executeswireless communication. The wireless communication interface 2133generally may comprise for example a BB processor 2134 and an RF circuit2135. The BB processor 2134 may execute for example coding/decoding,modulation/demodulation and multiplexing/demultiplexing, and executevarious types of signal processing for wireless communication.Meanwhile, the RF circuit 2135 may comprise for example a frequencymixer, a filter and an amplifier, and transmit and receive a wirelesssignal via the antenna 2137. The wireless communication interface 2133may also be a chip module on which a BB processor 2134 and an RF circuit2135 are integrated. As shown in FIG. 21, the wireless communicationinterface 2133 may comprise a plurality of BB processors 2134 and aplurality of RF circuits 2135. Although FIG. 21 shows an example inwhich the wireless communication interface 2133 comprises a plurality ofBB processors 2134 and a plurality of RF circuits 2135, the wirelesscommunication interface 2133 may also comprise a single BB processor2134 or a single RF circuit 2135.

In addition, besides the cellular communication schemes, the wirelesscommunication interface 2133 may support other types of wirelesscommunication schemes, such as a Device-to-Device (D2D) communicationscheme, a short range wireless communication scheme, a near fieldcommunication scheme and a wireless LAN scheme. In this case, for eachwireless communication scheme, the wireless communication interface 2133may comprise a BB processor 2134 and an RF circuit 2235.

Each of the antenna switches 2136 switches a connection destination ofthe antenna 2137 between a plurality of circuits included in thewireless communication interface 2133 (for example, circuits fordifferent wireless communication schemes).

Each of the antennas 2137 comprises a single or more antenna elements(such as a plurality of antenna elements included in an MIMO antenna),and is used for the communication interface 2133 to transmit and receivea wireless signal. As shown in FIG. 21, the automobile navigation device2120 may comprise a plurality of antennas 2137. Although FIG. 21 showsan example in which the automobile navigation device 2120 comprises aplurality of antennas 2137, the automobile navigation device 2120 mayalso comprise a single antenna 2137.

In addition, the automobile navigation device 2120 may comprise anantenna 2137 for each wireless communication scheme. In this case, theantenna switch 2136 may be omitted from the configuration of theautomobile navigation device 2120.

The battery 2138 supplies electric power to the respective blocks of theautomobile navigation device 2120 as shown in FIG. 21 via feeder lineswhich are partially shown as dashed lines in the figure. The battery2138 accumulates the electric power supplied from the vehicle.

In the automobile navigation device 2120 as shown in FIG. 21, thecommunication interfaces in the foregoing electronic devices 1000 and1100 may be realized by the wireless communication interface 2133. Atleast part of the functions of the evaluation unit, the determinationunit and the generation unit may also be implemented by the processor2121.

The technology of the disclosure may also be realized as an in-vehiclesystem (or vehicle) 2140 comprising one or more of the following blocks:the automobile navigation deice 2120, the in-vehicle network 2141 and avehicle module 2142. The vehicle module 2142 generates vehicle data(such as vehicle speed, engine speed and fault information), and outputsthe generated data to the in-vehicle network 2141.

Preferred embodiments of the present disclosure have been describedabove with reference to the drawings. However, the disclosure of courseis not limited to the above examples. Those skilled in the art canobtain various alterations and modifications within the scope of theappended claims, and it should be understood that these alterations andmodifications naturally will fall within the technical scope of thedisclosure.

For example, in the foregoing embodiments, a plurality of functionsincorporated in one unit may be implemented by separate devices.Alternatively, in the foregoing embodiments, a plurality of functionsimplemented by a plurality of units may be implemented by separatedevices, respectively. In addition, one of the foregoing functions maybe implemented by a plurality of units. Undoubtedly, such configurationis included within the technical scope of the disclosure.

In the specification, the steps described in the flowcharts not onlyinclude processing executed in the order according to a time sequencebut also include processing executed in parallel or separately but notnecessarily according to a time sequence. In addition, even if in stepsin which processing is executed according to a time sequence, the orderundoubtedly still can be appropriately changed.

Although the present disclosure and the advantages thereof have beendescribed in detail, it should be understood that various alterations,substitutions or transformations may be made without departing from thespirit and the scope of the present disclosure as defined by theappended claims. Moreover, terms “include” and “comprise” or any othervariants thereof in the embodiments of the present disclosure areintended to cover non-exclusive inclusion, such that a process, amethod, an article or an apparatus including a series of elements notonly includes those elements but also includes other elements notexplicitly listed or but also includes elements intrinsic to such aprocess, method, article or apparatus. In the absence of morelimitations, elements defined by expression “including one . . . ” donot exclude further existence of other identical elements in a process,a method, an article or an apparatus including the elements.

The invention claimed is:
 1. An electronic device at a user equipmentend in a wireless communication system, the electronic devicecomprising: processing circuitry configured to: estimate and reportwideband channel state information to a base station; determine whethera communication quality between the user equipment and the base stationis lower than a predetermined threshold; transmit a quality report, in acase where it is determined that the communication quality is lower thanthe predetermined threshold, to the base station; receive, from the basestation, a subband reference signal and an estimation instructionindicating that the electronic device is to estimate subband channelstate based on the subband reference signal; and generate subbandchannel state information to be sent to the base station according tothe subband reference signal.
 2. The electronic device according toclaim 1, wherein the generated subband channel state information is forthe base station to determine an effective precoding codebook based onthe subband channel state information.
 3. The electronic deviceaccording to claim 1, wherein the wideband channel state information isestimated and reported in response to a wideband reference signal fromthe base station.
 4. The electronic device according to claim 3, whereinthe subband reference signal corresponds to one or more subband channelsof a wideband corresponding to the wideband reference signal.
 5. Theelectronic device according to claim 2, the electronic device furthercomprising a transceiver configured to: transmit the subband channelstate information to the base station; and receive downlink controlinformation from the base station; the processing circuitry furtherconfigured to generate, in response to the downlink control information,the subband channel state information.
 6. The electronic deviceaccording to claim 1, wherein the subband channel state informationincludes subband channel quality indicator (CQI) or subband precedingmatrix indicator (PMI).
 7. The electronic device according to claim 1,wherein the subband reference signal includes Channel StateInformation-Reference Signal (CSI-RS).
 8. A method implemented withprocessing circuitry at an electronic device at a user equipment end ina wireless communication system, the method comprising: estimating andreporting wideband channel state information to a base station;determining whether a communication quality between the user equipmentand the base station is lower than a predetermined threshold;transmitting a quality report, in a case where it is determined that thecommunication quality is lower than the predetermined threshold, to thebase station; receiving, from the base station, a subband referencesignal and an estimation instruction indicating that the electronicdevice is to estimate subband channel state based on the subbandreference signal; and generating subband channel state information to besent to the base station according to the subband reference signal. 9.The method according to claim 8, wherein the generated subband channelstate information is for the base station to determine an effectiveprecoding codebook based on the subband channel state information. 10.The method according to claim 8, wherein the wideband channel stateinformation is estimated and reported in response to a widebandreference signal from the base station.
 11. The method according toclaim 10, wherein the subband reference signal corresponds to one ormore subband channels of a wideband corresponding to the widebandreference signal.
 12. The method according to claim 8, furthercomprising: transmitting, with a transceiver, the subband channel stateinformation to the base station; receiving, via the transceiver,downlink control information from the base station; and generating, inresponse to the downlink control information, the subband channel stateinformation.
 13. The method according to claim 8, wherein the subbandchannel state information includes subband channel quality indicator(CQI) or subband preceding matrix indicator (PMI).
 14. The methodaccording to claim 8, wherein the subband reference signal includesChannel State Information-Reference Signal (CSI-RS).
 15. Anon-transitory computer readable storage medium storing executableinstructions which when executed by processing circuitry at anelectronic device at a user equipment end in a wireless communicationsystem, causes the processing circuitry to perform a method comprising:estimating and reporting wideband channel state information to a basestation; determining whether a communication quality between the userequipment and the base station is lower than a predetermined threshold;transmitting a quality report, in a case where it is determined that thecommunication quality is lower than the predetermined threshold, to thebase station; receiving, from the base station, a subband referencesignal and an estimation instruction indicating that the electronicdevice is to estimate subband channel state based on the subbandreference signal; and generating subband channel state information to besent to the base station according to the subband reference signal. 16.The non-transitory computer readable storage medium according to claim15, wherein the generated subband channel state information is for thebase station to determine an effective precoding codebook based on thesubband channel state information.
 17. The non-transitory computerreadable storage medium according to claim 15, wherein the widebandchannel state information is estimated and reported in response to awideband reference signal from the base station.
 18. The non-transitorycomputer readable storage medium according to claim 15, furthercomprising: transmitting, with a transceiver, the subband channel stateinformation to the base station; receiving, via the transceiver,downlink control information from the base station; and generating, inresponse to the downlink control information, the subband channel stateinformation.
 19. The non-transitory computer readable storage mediumaccording to claim 15, wherein the subband channel state informationincludes subband channel quality indicator (CQI) or subband precedingmatrix indicator (PMI).
 20. The non-transitory computer readable storagemedium according to claim 15, wherein the subband reference signalincludes Channel State Information-Reference Signal (CSI-RS).